diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c90eaa80344017fd8a8e7555508a20949020f61f..02e09c0e98abe4e04c34e250c0a0df15e9fc43ff 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -86,7 +86,6 @@ struct cgroup_subsys_state {
enum {
CSS_ROOT, /* This CSS is the root of the subsystem */
CSS_REMOVED, /* This CSS is dead */
- CSS_CLEAR_CSS_REFS, /* @ss->__DEPRECATED_clear_css_refs */
};
/* Caller must verify that the css is not for root cgroup */
@@ -485,17 +484,6 @@ struct cgroup_subsys {
*/
bool use_id;
- /*
- * If %true, cgroup removal will try to clear css refs by retrying
- * ss->pre_destroy() until there's no css ref left. This behavior
- * is strictly for backward compatibility and will be removed as
- * soon as the current user (memcg) is updated.
- *
- * If %false, ss->pre_destroy() can't fail and cgroup removal won't
- * wait for css refs to drop to zero before proceeding.
- */
- bool __DEPRECATED_clear_css_refs;
-
#define MAX_CGROUP_TYPE_NAMELEN 32
const char *name;
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 79818507e444aa3050c9994841258292c294bd2e..8c605e2bdd1ae45698e45b96ebcd8f2ca489726c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -865,11 +865,8 @@ static int cgroup_call_pre_destroy(struct cgroup *cgrp)
continue;
ret = ss->pre_destroy(cgrp);
- if (ret) {
- /* ->pre_destroy() failure is being deprecated */
- WARN_ON_ONCE(!ss->__DEPRECATED_clear_css_refs);
+ if (WARN_ON_ONCE(ret))
break;
- }
}
return ret;
@@ -3901,14 +3898,12 @@ static void init_cgroup_css(struct cgroup_subsys_state *css,
cgrp->subsys[ss->subsys_id] = css;
/*
- * If !clear_css_refs, css holds an extra ref to @cgrp->dentry
- * which is put on the last css_put(). dput() requires process
- * context, which css_put() may be called without. @css->dput_work
- * will be used to invoke dput() asynchronously from css_put().
+ * css holds an extra ref to @cgrp->dentry which is put on the last
+ * css_put(). dput() requires process context, which css_put() may
+ * be called without. @css->dput_work will be used to invoke
+ * dput() asynchronously from css_put().
*/
INIT_WORK(&css->dput_work, css_dput_fn);
- if (ss->__DEPRECATED_clear_css_refs)
- set_bit(CSS_CLEAR_CSS_REFS, &css->flags);
}
/*
@@ -3978,10 +3973,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
if (err < 0)
goto err_remove;
- /* If !clear_css_refs, each css holds a ref to the cgroup's dentry */
+ /* each css holds a ref to the cgroup's dentry */
for_each_subsys(root, ss)
- if (!ss->__DEPRECATED_clear_css_refs)
- dget(dentry);
+ dget(dentry);
/* The cgroup directory was pre-locked for us */
BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex));
@@ -4066,71 +4060,6 @@ static int cgroup_has_css_refs(struct cgroup *cgrp)
return 0;
}
-/*
- * Atomically mark all (or else none) of the cgroup's CSS objects as
- * CSS_REMOVED. Return true on success, or false if the cgroup has
- * busy subsystems. Call with cgroup_mutex held
- *
- * Depending on whether a subsys has __DEPRECATED_clear_css_refs set or
- * not, cgroup removal behaves differently.
- *
- * If clear is set, css refcnt for the subsystem should be zero before
- * cgroup removal can be committed. This is implemented by
- * CGRP_WAIT_ON_RMDIR and retry logic around ->pre_destroy(), which may be
- * called multiple times until all css refcnts reach zero and is allowed to
- * veto removal on any invocation. This behavior is deprecated and will be
- * removed as soon as the existing user (memcg) is updated.
- *
- * If clear is not set, each css holds an extra reference to the cgroup's
- * dentry and cgroup removal proceeds regardless of css refs.
- * ->pre_destroy() will be called at least once and is not allowed to fail.
- * On the last put of each css, whenever that may be, the extra dentry ref
- * is put so that dentry destruction happens only after all css's are
- * released.
- */
-static int cgroup_clear_css_refs(struct cgroup *cgrp)
-{
- struct cgroup_subsys *ss;
- unsigned long flags;
- bool failed = false;
-
- local_irq_save(flags);
-
- /*
- * Block new css_tryget() by deactivating refcnt. If all refcnts
- * for subsystems w/ clear_css_refs set were 1 at the moment of
- * deactivation, we succeeded.
- */
- for_each_subsys(cgrp->root, ss) {
- struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
-
- WARN_ON(atomic_read(&css->refcnt) < 0);
- atomic_add(CSS_DEACT_BIAS, &css->refcnt);
-
- if (ss->__DEPRECATED_clear_css_refs)
- failed |= css_refcnt(css) != 1;
- }
-
- /*
- * If succeeded, set REMOVED and put all the base refs; otherwise,
- * restore refcnts to positive values. Either way, all in-progress
- * css_tryget() will be released.
- */
- for_each_subsys(cgrp->root, ss) {
- struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
-
- if (!failed) {
- set_bit(CSS_REMOVED, &css->flags);
- css_put(css);
- } else {
- atomic_sub(CSS_DEACT_BIAS, &css->refcnt);
- }
- }
-
- local_irq_restore(flags);
- return !failed;
-}
-
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
{
struct cgroup *cgrp = dentry->d_fsdata;
@@ -4138,10 +4067,10 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
struct cgroup *parent;
DEFINE_WAIT(wait);
struct cgroup_event *event, *tmp;
+ struct cgroup_subsys *ss;
int ret;
/* the vfs holds both inode->i_mutex already */
-again:
mutex_lock(&cgroup_mutex);
if (atomic_read(&cgrp->count) != 0) {
mutex_unlock(&cgroup_mutex);
@@ -4182,21 +4111,34 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
return -EBUSY;
}
prepare_to_wait(&cgroup_rmdir_waitq, &wait, TASK_INTERRUPTIBLE);
- if (!cgroup_clear_css_refs(cgrp)) {
- mutex_unlock(&cgroup_mutex);
- /*
- * Because someone may call cgroup_wakeup_rmdir_waiter() before
- * prepare_to_wait(), we need to check this flag.
- */
- if (test_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags))
- schedule();
- finish_wait(&cgroup_rmdir_waitq, &wait);
- clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
- if (signal_pending(current))
- return -EINTR;
- goto again;
+
+ local_irq_disable();
+
+ /* block new css_tryget() by deactivating refcnt */
+ for_each_subsys(cgrp->root, ss) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
+
+ WARN_ON(atomic_read(&css->refcnt) < 0);
+ atomic_add(CSS_DEACT_BIAS, &css->refcnt);
+ }
+
+ /*
+ * Set REMOVED. All in-progress css_tryget() will be released.
+ * Put all the base refs. Each css holds an extra reference to the
+ * cgroup's dentry and cgroup removal proceeds regardless of css
+ * refs. On the last put of each css, whenever that may be, the
+ * extra dentry ref is put so that dentry destruction happens only
+ * after all css's are released.
+ */
+ for_each_subsys(cgrp->root, ss) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
+
+ set_bit(CSS_REMOVED, &css->flags);
+ css_put(css);
}
- /* NO css_tryget() can success after here. */
+
+ local_irq_enable();
+
finish_wait(&cgroup_rmdir_waitq, &wait);
clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
@@ -4949,8 +4891,7 @@ void __css_put(struct cgroup_subsys_state *css)
cgroup_wakeup_rmdir_waiter(cgrp);
break;
case 0:
- if (!test_bit(CSS_CLEAR_CSS_REFS, &css->flags))
- schedule_work(&css->dput_work);
+ schedule_work(&css->dput_work);
break;
}
rcu_read_unlock();